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النتائج 251 - 260 من 539
Regional distribution of non-human H7N9 avian influenza virus detections in China and construction of a predictive model
2021
Huang, Zeying | Li, Haijun | Huang, Beixun
H7N9 avian influenza has broken out in Chinese poultry 10 times since 2013 and impacted the industry severely. Although the epidemic is currently under control, there is still a latent threat. Epidemiological surveillance data for non-human H7N9 avian influenza from April 2013 to April 2020 were used to analyse the regional distribution and spatial correlations of positivity rates in different months and years and before and after comprehensive immunisation. In addition, positivity rate monitoring data were disaggregated into a low-frequency and a high-frequency trend sequence by wavelet packet decomposition (WPD). The particle swarm optimisation algorithm was adopted to optimise the least squares support-vector machine (LS-SVM) model parameters to predict the low-frequency trend sequence, and the autoregressive integrated moving average (ARIMA) model was used to predict the high-frequency one. Ultimately, an LS-SVM-ARIMA combined model based on WPD was constructed. The virus positivity rate was the highest in late spring and early summer, and overall it fell significantly after comprehensive immunisation. Except for the year 2015 and the single month of December from 2013 to 2020, there was no significant spatiotemporal clustering in cumulative non-human H7N9 avian influenza virus detections. Compared with the ARIMA and LS-SVM models, the LS-SVM-ARIMA combined model based on WPD had the highest prediction accuracy. The mean absolute and root mean square errors were 2.4% and 2.0%, respectively. Low error measures prove the validity of this new prediction method and the combined model could be used for inference of future H7N9 avian influenza virus cases. Live poultry markets should be closed in late spring and early summer, and comprehensive H7N9 immunisation continued.
اظهر المزيد [+] اقل [-]Phytoncides in the prevention and therapy of blackhead disease and their effect on the turkey immune system
2021
Tykałowski, Bartłomiej | Śmiałek, Marcin | Kowalczyk, Joanna | Dziewulska, Daria | Stenzel, Tomasz | Koncicki, Andrzej
Turkey histomonosis poses a serious threat to poultry production due to the ban on the use of effective drugs. The aim of the study was to evaluate the influence of a phytoncidal feed supplement on the course of histomonosis. The preparation was also analysed for immunomodulatory properties. Clinical observations and production monitoring were conducted in a flock of turkeys with histomonosis from their 11ᵗʰ to 56ᵗʰ weeks of life which were treated with the adiCoxSᴼᴸPF soluble supplement in a dose of 2.5 mL/L water. Later the preparation was used in a preventive dose (1 mL/L). The influence on the immune system was evaluated in broiler turkeys having been given adiCoxSᴼᴸPF for 3 days in doses of 1 or 3 mL/L. The T and B lymphocyte percentages in turkey blood and spleen tissue were analysed with flow cytometry. ELISA was implemented to evaluate antibody titres after Ornithobacterium rhinotracheale vaccination, and biochemical analyses were performed to evaluate the supplement’s safety. AdiCoxSᴼᴸPF was found effective in therapy and prevention of histomonosis. Additionally, adiCoxSᴼᴸPF stimulated both humoral and cell-mediated immune mechanisms, without impairing the functions of internal organs. The treated turkeys also yielded better production results (eggs/hen, fertility, and hatchability). AdiCoxSᴼᴸPF possesses immunomodulatory properties and it can be used successfully in the prevention and therapy of histomonosis in turkeys.
اظهر المزيد [+] اقل [-]Prevalence of genetically modified soybean in animal feedingstuffs in Poland
2021
Sieradzki, Zbigniew | Mazur, Małgorzata | Król, Beata | Kwiatek, Krzysztof
Globally, genetically modified (GM) crops were grown on 191.7 million hectares in 2018, which were mostly sown with soybean, maize, cotton, oilseed rape, and rice. The most popular traits introduced through genetic modification include herbicide and pest insect resistance. The aim of this study was to identify and quantify genetically modified soybean used in animal feed in Poland. This research was based on the real-time PCR technique. All methods for GM soybean events were adopted from the EURL GMFF database of methods and previously verified to meet the minimum criteria of acceptance. Over 15 years of research, 665 samples were examined in total. The most common GM soybean event was MON40-3-2, tested for from the beginning of the investigation. Next, in decreasing order of frequency, were MON89788, MON87701, and A2704-12. In the majority of samples (606; 91%) GM soybeans were identified at a content level above the 0.9% GM content threshold for mandatory labelling. Only 59 soybean samples (9%) were identified as GM negative. GM negative results were mainly identified during the analyses in the last three years of the study, from 2017 to 2019. Our data clearly indicate that the majority of soybean used in Poland for animal feeding was genetically modified.
اظهر المزيد [+] اقل [-]Acrylamide-induced changes of granulopoiesis in porcine bone marrow
2021
Grzybowska, Dominika | Snarska, Anna
Due to the widely documented and diverse toxic effects of acrylamide, the authors decided to evaluate the impact of high and low doses of this compound on the process of granulopoiesis in porcine bone marrow. The experiment was conducted on 15 Danish Landrace pigs at the age of 8 weeks. The animals were randomly assigned into three equal groups (n = 5). Control animals received empty gelatine capsules as placebo. Animals in the first experimental group (the LD group) received a low dose of acrylamide of 0.5 μg/kg b.w./day, and animals in the second experimental group (the HD group) received a tenfold higher dose of acrylamide of 5 μg/kg b.w./day. Placebo and acrylamide capsules were administered with feed every morning for 28 days. Bone marrow was collected into tubes without an anticoagulant twice – before the first capsule administration (day 0) and on the 28ᵗʰ day of the study. After drying and staining, bone marrow smears were subjected to detailed cytological evaluation under a light microscope. Changes in cell morphology, i.e. degenerative changes in the cellular nuclei, were observed in both experimental groups. Both low and high doses of acrylamide decreased the number of segmented eosinophils, neutrophilic and segmented metamyelocytes, neutrophils, as well as basophils and basophilic metamyelocytes. Acrylamide at doses of 0.5 μg/kg b.w./day and 5 μg/kg b.w./day clearly influences porcine granulopoiesis.
اظهر المزيد [+] اقل [-]Antimicrobial resistance and virulence factor gene profiles of Enterococcus spp. isolated from giant panda oral cavities
2021
Zhong, Rui | Zhou, Ziyao | Liu, Haifeng | Zhong, Zhijun | Peng, Guangneng
The objective of this study was to determine the prevalence and characteristics of antimicrobial-resistant Enterococcus faecalis and E. faecium isolated from the oral cavities of captive giant pandas in China. The virulence-associated determinant and antimicrobial resistance genes were detected and antimicrobial susceptibility tests were performed on 54 strains of each bacterium. All isolates showed 100% multidrug resistance. E. faecalis isolates showed a higher percentage of strains resistant to gentamicin (48.1%), vancomycin (55.6%), linezolid (100%), and streptomycin (33.3%) than E. faecium isolates. The resistance genes of Enterococcus spp. were present to highly varying extents according to antibiotic type, their presence breaking down for E. faecalis and E. faecium respectively as aac(6')/aph(2″) 5.56% and 5.56%; aph(3')-Ⅲ 0% and 14.81%; ant(6)-I 0% and 3.7%; ant(4')-Ia 0% and 64.81%; tetL 20.37% and 100%; vanA 92.59% and 46.3%; vanB 0% and 0%; cfr 0% and 90.74%; optrA 96.3% and 3.7%; blaZ 0% and 1.85%; blaTEM 0% and 0%; tetA 20.37% and 0%; tetC 24.07% and 100%; tetM 0% and 0%; ermA 12.96% and 100%; ermB 5.56% and 3.7%; and ermC 0% and 1.85%.Virulence-associated determinants were detected in this research, which typically include efaA, gelE, asa1, ace, cylA, esp and hyl; however, the latter three were not detected. High proportions of the isolates carried the efaA, gelE, asa1, and ace genes. Respectively for E. faecalis and E. faecium their detection was efaA 98.1% and 85.2%; gelE 98.1% and 87%; asa1 92.6% and 87%; and ace 87% and 85.2%. This is the first study on the potential disease risk and antimicrobial-resistant characteristics of E. faecalis and E. faecium isolates in giant panda oral cavities. The results of this study show that the antimicrobial resistance rate of Enterococcus spp. isolated from the oral cavity of captive pandas is very high, and thus needs to be monitored.
اظهر المزيد [+] اقل [-]A pilot study on the effect of a novel feed additive containing exogenous enzymes, acidifiers, sodium butyrate and silicon dioxide nanoparticles on selected cellular immune indices and body weight gains of calves
2021
Szacawa, Ewelina | Dudek, Katarzyna | Bednarek, Dariusz | Pieszka, Marek | Bederska-Łojewska, Dorota
The rearing of calves is a difficult period for farmers due to health problems to which the animals are prone this time. Since the use of antibiotics as growth promoters has been forbidden, various innovative feed additives have been tested in many countries around the world. In this study, experimental (E) calves were supplemented with a novel feed additive consisting of the pancreatic-like enzymes protease and lipase, a fat-coated mixture of organic fumaric, malic, citric and sorbic acids, sodium butyrate and silicon dioxide nanoparticles. Control (C) calves received feed without additive. During the supplementation, white blood cell (WBC) counts with leukocyte differentiation, percentages of B lymphocytes and T lymphocytes and their subpopulations, phagocytic activity and oxidative burst of circulating monocytes and granulocytes were examined. Body weight (b.w.) gains of the calves were also monitored. The WBC counts in the E and C calves were within the reference ranges throughout the study. In the analysis of the percentages of the lymphocyte subpopulations, phagocytic activity and oxidative burst, no statistically significant differences were reported between the E and C groups. However, higher average daily body weight gains were obtained for the E calves. The study revealed that the examined feed additive did not modulate the immune response of the calves significantly. The tendency to higher daily average b.w. gains in the E calves than in the C calves suggests a beneficial effect of this feed additive.
اظهر المزيد [+] اقل [-]Effects of tyrosine kinase inhibitor-masitinib mesylate on canine mammary tumour cell lines
2021
Ustun-Alkan, Fulya | Bakırel, Tülay | Üstüner, Oya | Anlas, Ceren | Cinar, Suzan | Yıldırım, Funda | Gürel, Aydın
Masitinib mesylate, a selective tyrosine kinase inhibitor of the c-KIT receptor, is used for the treatment of mast cell tumours in dogs. Masitinib has previously been investigated in various cancers; however, its potential anticancer effect in canine mammary tumours (CMTs) is unknown. In the present paper, we investigated the antiproliferative effect of masitinib in CMT cells and its possible mechanisms of action. The effect of masitinib on the proliferation of CMT-U27 and CMT-U309 cells was assessed by MTT assay and DNA fragmentation. Flow cytometric analysis was used to measure the effect of masitinib on apoptosis and the cell cycle. Additionally, vascular endothelial growth factor levels (VEGF) were measured, and the proliferation marker Ki-67 was visualised in immunocytochemical stainings in CMT cells. Treatment with masitinib inhibited the proliferation of CMT cells in a concentration-dependent manner. Maximal apoptotic activity and DNA fragmentation were observed at approximately IC₅₀ of masitinib in both cell lines. In addition, cell cycle distribution was altered and VEGF levels and Ki-67 proliferation indices were decreased in masitinib-treated cells in comparison with control cells. In this study, masitinib suppressed cell proliferation concomitantly via induction of apoptosis and cell cycle arrest by decreasing VEGF levels and the Ki-67 proliferation index in CMT-U27 and CMT-U309 cells in vitro, suggesting its potential as a therapeutic tool in the clinical setting of mammary cancer treatment in dogs.
اظهر المزيد [+] اقل [-]Occurrence of selected pathogenic microorganisms in raw and processed eggs of snails of the Cornu genus
2021
Maćkowiak-Dryka, Monika | Gondek, Michał | Szkucik, Krzysztof
This study investigated the eggs of Polish-bred edible snails of the Cornu genus as a food and aimed to determine the presence of microorganisms in them of the Salmonella and Listeria genera and ascertain the number of coagulase-positive staphylococci. Raw material, semi-finished products, and the final product were collected during the production cycle. Testing for the presence of Salmonella spp. and Listeria spp. and measuring of the pathogenic staphylococci contamination level were carried out in accordance with ISO standards. Commercial biochemical tests were used for species identification of bacteria of the Enterobacteriaceae family and Staphylococcus genus. An API kit and a PCR protocol were utilised for species confirmation of the microorganisms of the Listeria genus. Neither Salmonella nor coagulase-positive staphylococci were found in any of the studied material. Bacteria of the Listeria genus were found in samples taken at every stage of production; however L. monocytogenes was confirmed in samples of the final product. The absence of Salmonella spp. and Staphylococcus aureus in samples of the final product indicates that the required hygiene standard was maintained in the production process of edible snail eggs. Nevertheless, the presence of L. monocytogenes in eggs of common garden snails may pose a potential risk to consumer health.
اظهر المزيد [+] اقل [-]Effect of negative energy balance on plasma metabolites, minerals, hormones, cytokines and ovarian follicular growth rate in Holstein dairy cows
2021
The aim of this study was to evaluate the effect of negative energy balance (NEB) on the final growth of the dominant ovarian follicle in Holstein cows. Cows at 14 to 21 d postpartum from an intensive dairy farm were randomly selected and allocated into a positive energy balance group (PEB, with β-hydroxybutyric acid (BHBA) level < 1.2 mmol/L, n = 15) and an NEB group (BHBA > 1.2 mmol/L, n = 15). Plasma samples were collected at 21, 50 and 55 d postpartum to assess the concentrations of energy metabolites, minerals, hormones and cytokines. Ovaries were examined by transrectal ultrasound on days 50 and 55 (120 hours later) to evaluate the diameter of the largest follicle. Compared with PEB cows, there were a more severe body condition loss and a lower milk yield in NEB cows (P < 0.05) and these had greater concentrations of plasma BHBA, non-esterified fatty acids, triglycerides, urea nitrogen, growth hormone, interleukin 6, and fibroblast growth factor 21 and lesser concentrations of plasma glucose, total cholesterol, insulin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, leptin, brain-derived neurotrophic factor and angiopoietin-like protein 8 on d 21 (P < 0.05), while plasma minerals were not affected by energy status (P > 0.05). These changes persisted until the end of the study period (50–55 days postpartum) resulting in a lower follicular growth rate for cows in the NEB than the PEB group. These observations indicate that follicular growth rate is associated with measurable changes in energy metabolite, hormone and cytokine concentrations caused by early postpartum NEB.
اظهر المزيد [+] اقل [-]Disorders in blood circulation as a probable cause of death in dogs infected with Babesia canis
2021
The purpose of the study was to investigate post-mortem changes in dogs infected with Babesia canis and to establish the probable cause of death of the affected animals. Cadavers of six dogs that did not survive babesiosis were collected. Necropsies were performed and samples of various organs were collected for histological examination. Necropsies and histological examinations revealed congestion and oedemata in various organs. Most of the dogs had ascites, hydrothorax or hydropericardium, pulmonary oedema, pulmonary, renal, hepatic, and cerebral congestion, and necrosis of cardiomyocytes. These results suggested disorders in blood circulation as the most probable cause of death. However, the pulmonary inflammatory response and cerebral babesiosis observed in some of these dogs could also be considered possible causes of death. This study also showed a possible role for renal congestion in the development of renal hypoxia and azotaemia in canine babesiosis.
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